archive/zzip: fix crash on corrupt ZIP file

Sometimes, zzip_file_read() returns 0 even though the end of the file
was not reached.  This causes assertion failures in
DecoderBridge::Read().

Closes https://github.com/MusicPlayerDaemon/MPD/issues/935

src/archive/plugins/ZzipArchivePlugin.cxx

@@ -32,6 +32,8 @@
 
 #include <zzip/zzip.h>
 
+#include <inttypes.h> /* for PRIoffset (PRIu64) */
+
 struct ZzipDir {
 	ZZIP_DIR *const dir;
 
@@ -151,6 +153,11 @@ ZzipInputStream::Read(void *ptr, size_t read_size)
 	if (nbytes < 0)
 		throw std::runtime_error("zzip_file_read() has failed");
 
+	if (nbytes == 0 && !IsEOF())
+		throw FormatRuntimeError("Unexpected end of file %s"
+					 " at %" PRIoffset " of %" PRIoffset,
+					 GetURI(), GetOffset(), GetSize());
+
 	offset = zzip_tell(file);
 	return nbytes;
 }